Head Thrust Research Articles

Role of the video head impulse test in the evaluation of vestibulo-ocular reflex in individuals with Parkinson's disease.

<p>Parkinson&rsquo;s disease (PD) is the most common movement disorder and the second most common neu&shy;rodegenerative disease of the central ner&shy;vous system. Dizziness is frequently reported by PD patients, yet there is a paucity of research focusing on the vestibulo-ocular reflex (VOR) in this population using high-frequency vestibular testing. This study aims to investigate the VOR in individuals with PD using the video head thrust test with and without suppression.&nbsp;</p>. <p>Forty individuals with PD and 40 healthy individuals were included in the study. According to the Hoehn-Yahr Scale, individuals with PD were defined as early stage with a score of 1&ndash;2.5 and middle to late stage with a score of 3 to 5. The Head Impulse Testing Paradigm (HIMP) and Suppression Head Impulse Testing Paradigm (SHIMP) were applied to all individuals.</p>. <p>No statistically significant difference was observed between the PD group and the control group in terms of semicircular canal (SCC) gains in both HIMP and SHIMP tests. No catch-up saccades were observed in the right anterior, right posterior, left anterior, and left posterior SCC planes in the PD and control groups. However, in the right lateral SCC plane 32 patients in the PD group had saccades, while 8 patients in the control group had saccades. In the left lateral SCC plane, 32 patients in the PD group and 9 patients in the control group had catch-up saccades. A statistically significant difference was observed in the number and amplitude of saccades in the right and left lateral SCC planes compared to the control group (p&lt;0.05). In addition, in the PD group, the amplitude, peak velocity, and latency of the anticompensatory saccades seen in SHIMP showed a statistically significant difference compared to the control group (p&lt;0.05).</p>. <p>VOR in the vertical SCC plane was not affected in individuals with PD. However, VOR in the lateral SCC plane was affected. It was concluded that when evaluating VOR with both HIMP and SHIMP in individuals with PD, the presence of catch-up saccades should be focused on and evaluated for possible vestibular dysfunction, even though SCC gains are normal. This study will contribute to a deeper understanding of vestibular function in PD, potentially informing better management strategies for dizziness in this population.&nbsp;</p>.

Vertical saccades during horizontal head impulses: a sign of posterior semicircular canal hypofunction.

We describe an uncharacteristic vestibular-ocular reflex (VOR) pattern, studied by video head impulse tests (VHIT) in patients suffering from unilateral isolated posterior semicircular canal (PSC) hypofunction. In these patients, we found an upward sliding of the eyes, followed by an oblique downward catch-up saccade during horizontal head impulse to the healthy side. We present a retrospective study of all VHIT exams presenting isolated PSC hypofunction between May 2020 and November 2022. We found 37 patients, which led to the discovery of such incongruent eye movement in 19 cases; their gain data are shown and compared to the remaining 18 cases in which such an anomaly was absent. A control group of 31 healthy subjects was recruited to define the reference criteria for VHIT gain values. The correlation between the amplitude of the vertical saccade and the relative functional imbalance of the vertical semicircular canals was studied. We have observed that in approximately half of the subjects with isolated CSP deficiency, there is a VOR anomaly. A possible pathophysiological explanation of the unbalanced effect of vertical semicircular canal stimulation of a labyrinth during horizontal head thrust toward the opposite side is proposed. The planar incongruity of the response of the VOR described here appears more evident at the onset of the CSP deficit. Current VHIT systems do not detect this incongruent eye reflex. They can lead to an error in gain evaluation (pseudo-deficit) of the lateral semicircular canal of the healthy side and problems in performing the test (trace rejected). In the future, software for VHIT should take into account the possibility of non-coplanar ocular responses to cephalic stimuli.

Vibration prediction and analysis of the main beam of the TBM based on a multiple linear regression model

The vibration of tunnel boring machine (TBM) is very difficult to monitor on sites, and related research on prediction methods is rare. Based on the field tunnelling test of a TBM in the Xinjiang Ehe project, the vibration information of the main beam of the TBM under different surrounding rock conditions is collected. The relationships among the tunnelling parameters, surrounding rock parameters and vibration parameters were studied. The results show that the penetration, cutter head speed, torque and thrust are important parameters affecting TBM vibration. In addition, the field penetration index and cutter head driving power index are significantly related to the root mean square of acceleration. Based on this, a multiple regression prediction model of TBM vibration is established. The model was verified and analysed via field projects, and the relative prediction error was less than 12%. This method can be used to predict the vibration of a TBM in real time through characteristic parameters without the use of a traditional monitoring system. This approach is highly important for determining the status of TBM equipment in real time.

Preseason Measures of Cervical Spine Function, Vestibulo-Ocular Reflex, Dynamic Balance, and Divided Attention in Youth Ice Hockey Players.

OBJECTIVES: Report typical scores and examine preseason cervical spine, vestibulo-ocular reflex, dynamic balance, and divided attention measures in competitive youth ice hockey players aged 10 to 18 years with and without a previous concussion history. DESIGN: Cross-sectional secondary analysis. METHODS: The exposure of interest was self-reported history of concussion. The main outcomes were cervical spine measures (Cervical Flexor Endurance [CFE; seconds], Cervical Flexion-Rotation Test [normal/abnormal], Anterolateral Cervical Spine Strength [kilograms], Head Perturbation Test (/8), and Joint Position Error [JPE; centimeters]), vestibulo-ocular reflex (Dynamic Visual Acuity [logMAR], Head Thrust Test [Positive/Negative]), dynamic balance (Functional Gait Assessment [/30]) and divided attention (Walking While Talking Test [seconds]). Multivariable linear or logistic regression, adjusted for age-group, sex, level of play, and clustered by team, were used to assess potential differences by concussion history. RESULTS: We included data from 2311 participants in this study (87.2% male, 12.8% female, 39.0% reported a previous concussion). No differences by concussion history were found across any of the measures (P values range: 0.17-0.99). Measures of cervical spine function and divided attention differed by age group (eg, Median Left Anterolateral Cervical Spine Strength [kilograms] for males: U13 = 7.46, U15 = 9.10, U18 = 9.67). CONCLUSION: Clinical outcomes scores in youth ice hockey players did not differ by concussion history. Performance on cervical spine strength, CFE, and JPE test outcomes may improve with age, highlighting the importance of developmental considerations when interpreting test scores. J Orthop Sports Phys Ther 2024;54(3):1-11. Epub 30 November 2023. doi:10.2519/jospt.2023.11958.

Endemic fish calling: Acoustics and reproductive behaviour of the Neretva dwarf goby Orsinigobius croaticus.

The Neretva dwarf goby Orsinigobius croaticus (Gobiiformes, Gobionellidae) is an endemic fish native to the freshwaters of the Adriatic Basin in Croatia and Bosnia and Herzegovina, a Mediterranean Biodiversity Hotspot. Due to its limited distribution range, specific karst habitat and endangered status, laboratory studies on reproductive biology are scarce but crucial. Herein, we investigated the sound production and acoustic behaviour of the endangered O. croaticus during reproductive intersexual laboratory encounters, utilising an interdisciplinary approach. We also performed dissections and micro-computed tomography (μCT) scanning of the pectoral girdle to explore its potential involvement in sound production. Finally, comparative acoustic analysis was conducted on sounds produced by previously recorded soniferous sand gobies to investigate whether acoustic features are species-specific. The endemic O. croaticus is a soniferous species. Males of this species emit pulsatile sounds composed of a variable number of short (~15 ms) consecutive pulses when interacting with females, usually during the pre-spawning phase in the nest, but also during courtship outside the nest. Pulsatile sounds were low-frequency and short pulse trains (~140 Hz, <1000 ms). Male visual behaviour rate was higher when co-occurring with sounds and females entered the male's nest significantly more frequently when sounds were present. Characteristic body movements accompanied male sound production, such as head thrust and fin spreading. Furthermore, μCT scans and dissections suggest that O. croaticus shares certain anatomical similarities of the pectoral girdle (i.e. osseous elements and arrangement of levator pectoralis muscles) to previously studied sand gobies that could be involved in sound production. Multivariate comparisons, using sounds produced by eight soniferous European sand gobies, effectively distinguished soniferous (and sympatric) species based on their acoustic properties. However, the discrimination success decreased when temperature-dependent features (sound duration and pulse repetition rate) were excluded from the analysis. Therefore, we suggest both spectral and temporal features are important for the acoustic differentiation of sand gobies.

Noise Reduction of TBM Big Tunneling Data by Butterworth Filter

The location of a Tunnel Boring Machine (TBM) is prone to external environmental and internal system noise interference. To address TBM vibration characteristics, this study analyzed the sources of excavation data noise, the need for noise reduction, and the methods used, using excavation speed as the prime example. We validated the results through three actual tunnel projects. Our research showed that excavation parameters automatically collected by the TBM, such as excavation speed, cutter head thrust, and cutter head torque, contain noise and require filtering and noise reduction before data mining. Different cutoff frequencies correspond to varying filtering effects, and after considering both smoothness and accuracy, we recommend setting the Butterworth filter’s cutoff frequency to 0.1.

Advances in dynamic visual acuity test research.

The dynamic visual acuity test (DVAT) is a functional evaluation tool for the impairment and compensation of the vestibular system, which could reflect the Vestibulo-ocular reflex (VOR) function. We present an overview of DVAT research, displaying recent advances in test methods, application, and influencing factors; and discussing the clinical value of DVAT to provide a reference for clinical application. There are two primary types of DVAT: dynamic-object DVAT and static-object DVAT. For the latter, in addition to the traditional bedside DVAT, there are numerous other approaches, including Computerized DVAT (cDVAT), DVAT on a treadmill, DVAT on a rotary, head thrust DVA (htDVA) and functional head impulse testing (fHIT), gaze shift dynamic visual acuity with walking (gsDVA), translational dynamic visual acuity test (tDVAT), pediatric DVAT. The results of DAVT are affected by subject [occupation, static visual acuity (SVA), age, eyeglass lenses], testing methods, caffeine, and alcohol. DVAT has numerous clinical applications, such as screening for vestibular impairment, assessing vestibular rehabilitation, predicting fall risk, and evaluating ophthalmology-related disorders, vestibular disorders, and central system disorders.

Visual Development in a Patient with Infantile-Onset Saccade Initiation Delay

Congenital ocular motor apraxia (COMA), also known as infantile-onset saccade initiation delay (ISID), is characterized by the inability to initiate volitional horizontal saccades. This five-month-old girl showed constant rapid movements to right or left one week after birth. After four months, she began thrusting her head from left to right when following target objects. She was diagnosed with COMA/ISID. At 4 years of age, head thrust became less evident. She first uttered meaningful words at 5 years of age, and spoke in sentences by 6 years of age. At 6 years of age, visual acuity was 1.0 in both eyes at 1 m. Head thrust disappeared at almost 6 years of age. She could not start crawling and sustaining a sitting position due to hypotonia. Clinicians should be aware of visual development in COMA/ISID and should look for them during the assessment of these children.

The relationship between balance and flu-like symptoms: a medical condition that needs attention

Objective: In general, while upper respiratory tract viruses cause flu-like complaints, balance problems associated with these viruses are often overlooked. It has been a long time since the first appearance of Covid-19, but unfortunately, there is still no fully effective treatment for this disease. Along with balance manifestations, especially several vestibular symptoms such as dizziness, vertigo, and tinnitus are described as common clinical manifestations in COVID-19. In our study, we investigated the effects of Covid-19 on the balance system with routine balance tests and we tried to localize a possible disorder in the balance system. Materials and Methods: Volunteers were divided into two groups. The number of volunteers in each group was thirty. The first group consisted of SARS-CoV-2-positive patients and the second group consisted of healthy people. Spontaneous nystagmus determination, Romberg test, Fukuda stepping test (FST), head thrust test (HTT), head shake test (HST), finger-nose test, and tandem walking test were applied. Results: The lateral fall in the Romberg test, rotation in the FST, and nystagmus in the HST are significant in Group 1 (p&lt;0.001), (p&lt;0.001), (p&lt;0.03). The relationship between the fall side in the Romberg test and the direction of rotation in the FST were found to be significant in Group 1 (p&lt;0.001). Similarly, the relationship between the direction of rotation in the FST and the nys-tagmus direction in the HST, and the direction of the saccadic correction in the HTT were found to be sig-nificant (p&lt;0.026), (p&lt;0.010). Conclusion: In SARS-CoV-2 positive patients, the balance system, especially the peripheric vestibular system, may be affected even if the patients do not have obvious complaints about balance. Routine balance tests that can be performed quickly in the outpatient clinic can be used effectively for the evaluation of balance.

The impact of rotor configurations on hemodynamic features, hemocompatibility and dynamic balance of the centrifugal blood pump: A numerical study.

To investigate the effect of rotor design configuration on hemodynamic features, hemocompatibility and dynamic balance of blood pumps. Computational fluid dynamics was employed to investigate the effects of rotor type (closed impeller, semi-open impeller), clearance height and back vanes on blood pump performance. In particular, the Eulerian hemolysis model based on a power-law function and the Lagrangian thrombus model with integrated stress accumulation and residence time were applied to evaluate the hemocompatibility of the blood pump. This study shows that compared to the closed impeller, the semi-open impeller can improve hemolysis at a slight sacrifice in head pressure, but increase the risk of thrombogenic potential and disrupt rotor dynamic balance. For the semi-open impeller, the pressure head, hemolysis, and axial thrust of the blood pump decrease with increasing front clearance, and the risk of thrombosis increases first and then decreases with increasing front clearance. Variations in back clearance have little effect on pressure head, but larger on back clearance, worsens hemolysis, thrombogenic potential and rotor dynamic balance. The employment of back vanes has little effect on the pressure head. All back vanes configurations have an increased risk of hemolysis in the blood pump but are beneficial for the improvement of the rotor dynamic balance of the blood pump. Reasonable back vanes configuration (higher height, wider width, longer length and more number) decreases the flow separation, increases the velocity of blood in the back clearance, and reduces the risk of blood pooling and thrombosis. It was also found that hemolysis index (HI) was highly negatively correlated with pressure difference between the top and back clearances (r=-.87), and thrombogenic potential was positively correlated with pressure difference between the top and back clearances (r=.71). This study found that rotor type, clearance height, and back vanes significantly affect the hydraulic performance, hemocompatibility and rotor dynamic balance of centrifugal blood pumps through secondary flow. These parameters should be carefully selected when designing and optimizing centrifugal blood pumps for improving the blood pump clinical outcomes.

Determining the Agreement Between Common Measures Related to Vestibulo-ocular Reflex Function After a Mild Traumatic Brain Injury in Children and Adolescents

ObjectiveTo (1) determine the level of agreement between symptom provocation and performance-based tests of vestibulo-ocular reflex (VOR) function after pediatric mild traumatic brain injury (mTBI) and (2) describe the level of symptom provocation induced by a VOR task in individuals with and without cervical findings. DesignCross-sectional. SettingThis study was conducted at a tertiary care pediatric hospital. ParticipantsA total of 101 participants (N=101) aged 6-18 years within 3 weeks of mTBI diagnosis were included (54.5% female; mean age, 13.92±2.63 years; mean time since injury at assessment, 18.26±6.16 days). InterventionsNone. Main Outcome MeasuresSymptom provocation (Vestibular/Ocular Motor Screening tool), performance (clinician-observed VOR performance, head thrust test [HTT], computerized dynamic visual acuity test, video head impulse test), and cervical impairment (cervical flexion-rotation test, range of motion test, self-reported neck pain). Agreement was evaluated using Cohen's κ statistic. ResultsNo outcomes demonstrated agreement with symptom provocation (κ=−0.15 to 0.14). Fair agreement demonstrated between clinician-observed VOR performance and HTT (κ=0.32), with little to no agreement demonstrated between other measures. Proportions reporting test-induced dizziness and headache were greater among individuals with cervical findings (29.1%-41.8%) than without (2.3%-6.8%). ConclusionsFindings support that symptom provocation and performance-based tests measure different constructs and thus have distinct roles when assessing VOR function. Findings suggest results from measures of symptom provocation may be influenced by coexisting cervical impairments, underlining the value of assessing for cervical injury after pediatric mTBI.

Efficacy and Durability of Intratympanic Gentamicin Treatment for Meniere's Disease.

Objective: To study the success of intratympanic gentamicin (ITG) treatment in reducing vertigo attacks in Meniere's disease (MD) and the value of the Halmagyi head thrust test (HTT) in predicting treatment durability.Study Design: Retrospective cohort study.Setting: Tertiary care vestibular clinic.Patients: Unilateral MD patients treated with ITG from 2006–2019 with ≥6 months follow-up.Main Outcome Measures: Demographics, audiometric data, subjective symptomatology, and HTT results were collected. Treatment success was defined as sufficient symptom relief. Treatment failure indicated vertigo control of less than 6 months duration. Treatment relapse indicated vertigo recurrence after 6 months.Results: Of 255 patients, treatment success, failure, and relapse occurred in 226 (88.6%), 29 (11.4%), and 121 (47.1%) patients, respectively. 48 (18.8%) patients who failed to respond or relapsed underwent labyrinthectomy. Mean follow-up time was 3.7 yrs (range 0.5–12.8). After ITG treatment, 25% patients reported worse hearing; mean pure tone average (PTA) increased by 18.6 ± 11.3 dB and mean word recognition score (WRS) decreased by 33 ± 21%. Of the 148 patients with negative pre-treatment HHT, 103 (69.6%) converted to positive after ITG treatment. Mean time-to-relapse in the converted and non-converted HTT cohorts was significantly different (49.7 vs. 27.0 months, p = 0.009) even after adjusting for gender, age, laterality, duration of symptoms, and number of ITG treatments. There were no significant differences between the two groups in hearing outcomes or subjective symptoms (e.g. lingering disequilibrium).Conclusions: ITG treatment effectively reduces the number of vertigo attacks in MD. HTT is valuable in predicting durability of treatment benefit.

Physical model test on the influence of the cutter head opening ratio on slurry shield tunnelling in a cobble layer

To study the influence of the opening ratio of a cutter head on slurry shield tunnelling in a cobble stratum, a slurry shield test system that could realize the action of a cutter head and the automatic circulation of the slurry was developed. The mechanical response of cobble stratum during excavation and the instability of the excavation face in the slurry shield tunnel was studied. Moreover, the influences of the cutter head opening ratio on the shield parameters, surface settlement and failure mode of the excavation face were investigated. Finally, the opening ratios adaptability for the slurry shield in the cobble strata was discussed. Results show that the smaller the opening ratio is, the smaller the active failure chamber pressure and ultimate support ratio will be, as well as the settlement area during active failure. With an increase in the opening ratio, the active failure mode of the excavation surface changes from local slip failure to integral slip failure, and the volume of failure soil increases. The cutter head thrust and torque decrease with an increase in the opening ratio. The increase in shield thrust induced by a low opening ratio can be attributed to three factors, i.e. the increasing contact area between the cutter head and the excavation face, a large friction resistance between shield shell and stratum and the slurry cake phenomenon on the face of the cutter head. A modified theoretical calculation method suitable for cutter head torque of slurry shield in cobble stratum was proposed based on the experimental results. Finally, the opening ratios adaptability of the slurry shield in the cobble stratum was obtained.

Editors' Note: Opinion and Special Articles: Remote Evaluation of Acute Vertigo: Strategies and Technological Considerations

In “Opinion and Special Articles: Remote Evaluation of Acute Vertigo: Strategies and Technological Considerations,” Green et al. discussed the telemedicine approach to a patient with acute vertigo by describing a modified version of the penlight-cover test to detect nystagmus, the alternate-cover test to check for a skew deviation and techniques to perform a virtual Dix-Hallpike maneuver and the head thrust test. Tjell agreed with the strategies described, but reported they may be challenging in a busy emergency department, and indicated a preference for 3 different assessments including the Romberg test, the horizontal smooth pursuit eye movement test, and tragal pressure. Green et al. noted that evaluation of nystagmus by smooth pursuit has pitfalls and the diagnostic value of tragal compression is unclear. They suggested that a very large multicenter international trial would be needed to clarify whether there is a difference in diagnostic accuracy between their proposed batteries or a combination of their tests. In “Opinion and Special Articles: Remote Evaluation of Acute Vertigo: Strategies and Technological Considerations,” Green et al. discussed the telemedicine approach to a patient with acute vertigo by describing a modified version of the penlight-cover test to detect nystagmus, the alternate-cover test to check for a skew deviation and techniques to perform a virtual Dix-Hallpike maneuver and the head thrust test. Tjell agreed with the strategies described, but reported they may be challenging in a busy emergency department, and indicated a preference for 3 different assessments including the Romberg test, the horizontal smooth pursuit eye movement test, and tragal pressure. Green et al. noted that evaluation of nystagmus by smooth pursuit has pitfalls and the diagnostic value of tragal compression is unclear. They suggested that a very large multicenter international trial would be needed to clarify whether there is a difference in diagnostic accuracy between their proposed batteries or a combination of their tests.

Determining the Agreement Between Common Measures Of VOR Function After A Mild Traumatic Brain Injury in Children and Adolescents

<h3>Research Objectives</h3> Alterations to vestibulo-ocular reflex (VOR) function (1-3) and cervical spine injury (4-6) may contribute to dizziness reported following pediatric mild traumatic brain injury (mTBI). Moreover, dizziness has been correlated with a more negative prognosis. While various measures are used to assess VOR function, there is no consensus on what the optimal battery of tests may be. The influence of cervical injury on findings from these tests remains unclear. Objectives: i) to determine the level of agreement between symptom- and performance-based tests of VOR function in a pediatric mTBI sample; ii) to characterize the level of symptom provocation induced by VOR tests in individuals with and without cervical findings. <h3>Design</h3> Cross-sectional study. <h3>Setting</h3> Tertiary care pediatric hospital. <h3>Participants</h3> 101 participants (54.5% female), mean age 13.92 years (SD 2.63), completed a VOR assessment (mean time since injury 18.26 days (SD 6.16)). <h3>Interventions</h3> N/A. <h3>Main Outcome Measures</h3> Symptom provocation was measured by the Vestibular/ocular motor screening tool (VOMS). Performance was measured by VOMS VOR performance, the head thrust test (HTT), the computerized dynamic visual acuity test, and the video head impulse test. Cervical impairment was measured by the cervical flexion rotation test, range of motion test and self-reported neck pain. <h3>Results</h3> No outcomes demonstrated agreement with VOR symptom provocation (k=-0.15-0.14). Among performance-based measures, fair agreement was demonstrated between VOMS VOR performance and the clinical HTT (k=0.32), while little to no agreement was demonstrated between the remaining measures. VOR dizziness symptoms were reported in a greater proportion of individuals with cervical findings (41.1-41.8%) than without (2.3-6.8%). <h3>Conclusions</h3> The findings indicate i) that symptom-based VOR tests measure a different construct than performance-based tests, ii) the distinct role of each measure when assessing VOR function should be further understood, and iii) cervical injury may contribute to symptoms induced by tests of VOR function. <h3>Author(s) Disclosures</h3> The authors have no conflicts of interest to disclose. This study was funded by an ERA-Net NEURON JTC Cofund Program.

The effect of high-intensity physical exertion on measures of cervical spine, vestibular/ocular-motor screening, and vestibulo-ocular reflex function in university level collision and combative sport athletes

ObjectivesTo examine how high-intensity physical exertion affects clinical measures of cervical spine (CSp), vestibular/ocular motor screen (VOMS), and vestibulo-ocular reflex (VOR) function. DesignCase series. SettingSports Medicine Centre. ParticipantsA total of 37 athletes consented to participate (22 rugby, 15 wrestling; 9 men, 28 women; median age = 19 years [range 17–23 years]). Main outcome measuresOutcome measures included tests of CSp (cervical flexor endurance, head perturbation test, cervical flexion rotation test and anterolateral strength), VOR (head thrust test and dynamic visual acuity [DVA]), and a quantified version of the VOMS. These metrics were assessed prior to and after completing the 30–15 Intermittent Fitness Test. Bland-Altman plots and Wilcoxon signed-rank tests were utilized to analyze the data using an alpha of p < 0.004. ResultsCervical anterolateral strength (kg) was reduced post-exertion on the left (z = 3.87; p < 0.001), but not on the right between conditions (z = −1.49; p = 0.14). Athletes reported increased dizziness (z = −3.55; p = 0.004) and had reduced DVA following exertion (z = −2.78; p < 0.001). All other metrics were not significantly different following exertion (p > 0.011). ConclusionReduced performance on DVA, decreased left-anterolateral strength, and increased dizziness occurred following high-intensity exertion in varsity collision and combative athletes, which has implications for sideline screening for sport-related concussion.

Prevalence of Vestibular Disorders in Independent People Over 50 That Experience Dizziness.

People aged over 50 are the most likely to present to a physician for dizziness. It is important to identify the main cause of dizziness in order to develop the best treatment approach. Our goal was to determine the prevalence of benign paroxysmal positional vertigo (BPPV), and peripheral and central vestibular function in people that had experienced dizziness within the past year aged over 50. One hundred and ninety three community-dwelling participants aged 51–92 (68 ± 8.7 years; 117 females) were tested using the clinical and video head impulse test (cHIT and vHIT) to test high-frequency vestibular organ function; the head thrust dynamic visual acuity (htDVA) test to test high-frequency visual-stability; the dizziness handicap inventory (DHI) to measure the impact of dizziness; as well as sinusoidal and unidirectional rotational chair testing to test low- to mid-frequency peripheral and central vestibular function. From these assessments we computed the following measures: HIT gain; htDVA score; DHI score; sinusoidal (whole-body; 0.1–2 Hz with 30°/s peak-velocity) vestibulo-ocular reflex (VOR) gain and phase; transient (whole-body, 150°/s2 acceleration to 50°/s constant velocity) VOR gain and time constant; optokinetic nystagmus (OKN) gain and time constant (whole-body, 50°/s constant velocity rotation). Our study showed that BPPV, and peripheral or central vestibular hypofunction were present in 34% of participants, suggesting a vestibular cause to their dizziness. Over half (57%) of these with a likely vestibular cause had BPPV, which is more than twice the percentage reported in other dizzy clinic studies. Our findings suggest that the physical DHI score and VOR time constant were best at detecting those with non-BPPV vestibular loss, but should always be used in conjunction with cHIT or vHIT, and that the htDVA score and vHIT gain were best at detecting differences between ipsilesional and contralesional sides.

Routine Vestibular Function Assessment in Children With Congenital CMV: Are We Ready?

Routine Vestibular Function Assessment in Children With Congenital CMV: Are We Ready?

Is the bedside head impulse test useful in emergency decision making for nonexpert routine clinical practice?

In 1988, Halmagyi and Curthoys reported the clinical interest of bedside Head Impulse Test (bHIT) for vestibular system examination. Indeed, vestibulo-ocular reflex (VOR) deficit can be clinically demonstrated by the observation of a corrective refixation saccade immediately following head thrust. Testing vestibulo-ocular reflex at this high frequency rotation specifically asks for the action of direct short latency VOR pathway from the labyrinths to the extraocular muscles.

Dizziness

Dizziness is the quintessential symptom presentation in all of clinical medicine. It is a common reason that patients present to a physician. This chapter provides background information about the vestibular system, then reviews key aspects of history-taking and examination of the patient, then discusses specific disorders and common presentation types. Throughout the chapter the focus is on neurologic and vestibular disorders. Normal vestibular anatomy and physiology are discussed, followed by recommendations for history-taking and the physical examination. Specific disorders that cause dizziness are explored, along with common causes of non-specific dizziness. Common presentations are discussed, including acute severe dizziness, recurrent attacks, and recurrent positional vertigo. Finally, the chapter looks at laboratory investigations in diagnosis and management. Figures include population prevalence of dizziness symptoms, the anatomy of inner structures, primary afferent vestibular nerve activity, the head thrust test, the Dix-Hallpike maneuver, the supine positional test, the canalith repositioning procedure, and the barbecue roll maneuver. Tables list physiologic properties and clinical features of the components of the peripheral vestibular system, information to be acquired from history of the present illness, common symptoms patients report as dizziness, examination components, distinguishing among common peripheral and central vertigo syndromes, common causes of nonspecific dizziness, types of dizziness presentations, relevant imaging abnormalities on neuroimaging studies, vestibular testing components, and medical therapy for symptomatic dizziness. This review contains 8 highly rendered figures, 10 tables, and 68 references.